1. Field of the Invention
The present invention is related to fluidic elements and, more particularly, is directed towards a fluidic element which consists of a plurality of substantially identical fine blanked laminate plates.
2. Description of the Prior Art
One of the major problems facing a designer of fluidic systems concerns the ever present null off-set due to supply pressure or temperature variations. This problem is present, for example, in fluidic elements known as the laminar proportional amplifier and laminar jet rate sensor. Each of these components, as well as other components, utilize a plurality of extremely thin metal laminate plates which have the appropriate fluid passages formed therein.
The problem of null off-set is caused by geometric imperfections in the plates which inherently result from the manufacturing process. Typical prior art manufacturing processes include machining and metal etching of the individual laminate elements. For these two techniques, it is almost impossible to produce a symmetrical fluidic element, such as a laminar proportional amplifier. Furthermore, the machining and metal etching manufacturing techniques produce geometric imperfections in these elements which are random in nature. Therefore, it is extremely difficult to compensate for null off-set with randomly imperfect elements. As a result, with prior art techniques it is impossible to construct fluidic elements without null off-set over the supply pressure range. While many attempts have been advanced to minimize this problem, unfortunately the problem persists.
A manufacturing technique known as fine blanking has proven helpful in eliminating the random variations in the geometrical imperfections. Thus, even though it is still impossible to produce a perfectly symmetrical element, laminates which are produced by fine blanking from the same set of dies have demonstrated essentially the same mechanical bias. Accordingly, while not eliminating the null off-set problem, at least those elements produced by fine blanking provide a predictable null off-set which can be compensated.